Effect of Inoculation and Casting Modulus on the as Cast Microstructure of ‎Austenitic Manganese Iron with Nodular Graphite

Document Type : Original Research Article

Authors

1 MSc Student in Materials Engineering, Babol Noshirvani University of Technology, Babol, Iran

2 BSc Student in Materials Engineering, Babol Noshirvani University of Technology.‎

3 Associate Professor, Faculty of Materials and Industrial Engineering, , Babol Noshirvani University of Technology

10.22034/frj.2021.205511.1103

Abstract

In this paper, the effects of grain refiner amount, its addition method and the casting modulus (wall thickness) on the solidification microstructure of austenitic nodular graphite cast iron with 5 weight percent manganese were investigated. For this purpose, the inoculation was performed with ferrosilicon zirconium after spheroidizing with ferrosilicon magnesium. The grain refiner additions were performed using two basic method, ladle inoculation and pouring stream inoculation in different amounts (0, 0.1, 0.2 and 0.3% by weight). In addition, the casting process was performed in the step form sand-sodium silicate binder mold with 5, 10 and 20 mm thicknesses. Microstructural evaluations and hardness measuring were achieved using the optical and electron microscopes, EDS, MIP4 visual analysis and Rockwell C test method. The results showed that the as cast microstructure of the cast iron consists of nodular graphite and eutectic carbide at the pearlitic matrix. The amount of eutectic carbides and graphite nodule count increase and the amount of pearlite and the size of the graphite’s decrease by decreasing the mold thickness.  For all casting modulus (wall thicknesses), the inoculation process decreases the amount of eutectic carbide and graphite size and increases the graphite nodule count and its volume fraction. In addition, it was observed that the pouring stream inoculation is more effective than the ladle inoculation.

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References

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History

  • Receive Date: 16 October 2019
  • Revise Date: 31 July 2021
  • Accept Date: 25 August 2021

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